Finding the Third Proportional to 21,000 and 31,380

Step by Step Solution

1. Step 1: Write the proportion equation
   21,000 : 31,380 = 31,380 : x
2. Step 2: Convert to fraction form
   21,000/31,380 = 31,380/x
3. Step 3: Cross multiply
   21,000x = 31,380 × 31,380
4. Step 4: Simplify right side
   21,000x = 984,704,400
5. Step 5: Solve for x
   x = 984,704,400/21,000
6. Step 6: Final answer
   x = 46,890.69